Acquired immune deficiency disease (AIDS) leads to the development of certain cancers, particularly Kaposi's and B-cell lymphomas. This disease is caused by a retrovirus (HTLV-III) which kills T helper lymphocytes in vivo and in vitro, and which uses the T helper-specific marker (OKT4) as a receptor. Infected cells retain a persistent high level of unintegrated provirus genomes, from which mRNA and progency viral RNA synthesis probably occurs. AIDS victims develop Burkitt's lymphomas (BL) containing Epstein-Barr (EBV) genomes. It is unclear if antiviral treatment of HTLV-III would abrogate the risk of BL in AIDS patients. We propose to study HTLV-III infection in two ways. 1) After toxicity testing, we will test experimental drugs avilable to us for ability to prevent HTLV-III infection, expression, and virus production in susceptible cells. We will also examine the effect of drugs on intracellular levels of integrated and unintegrated virus DNA copies, and correlate this data with virus-caused cytopathic effect, using Northern, Southern, and Western blots, and reverse transcriptase and plaque assays. We will then determine dose-response curves and therapeutic indices. Nontoxic drugss that have significant antiviral activity will be screened for their effect on T-cell function in vitro. We will also test for virus recrudescence after drug treatment of persistently infected cells, and for development of drug resistence. 2) Studies of the possible interaction of HLTV-III and EBV in B-lymphocytes. As HTLV-III depletes T4 cells in vivo, B-cells may provide a reservoir for the virus. Dually infected (EBV + HTLV-III) cells have been isolated from AIDS patients. We will prepare the permissiveness of EBV- and EBV+ B-cells lines and primary cells to determine if EBV facilitates HTLV-III infection. In parallel, we will examine the same cell lines by flow cytometry for the OKT4 marker to determine if EBV may be able to induce this molecule on B-cells. At the molecular level, we propose to study possible trans-activation of the HTLV-III promoter by EBV.